This invention relates to a seal ring and more particularly to a seal ring exhibiting a good sealing performance with respect to a metallic surface even under high load and high temperature conditions.
The seal rings maintaining a good sealing performance with respect to a metallic surface even under high load and high temperature conditions are useful in many different technical fields. Such seal rings are particularly suitable for use, for example, with the cylinder direct injecting fuel injection valve mounted to cylinder for injecting fuel directly into cylinders.
The cylinder direct injecting fuel injection valve mounted to the cylinder of an internal combustion engine must endure severe environmental conditions peculiar to the fuel direct injection. The performances required under these conditions include the mechanical strength resisting to the cylinder heat and vibration and the mechanical strength resisting to the high pressure and high temperature of the burning gas within the combustion chamber as well as the sealing performance for preventing the leaks of the fuel and burning gas, the required electric and magnetic characteristics and resistance to the chemical components or residual components of the fuel and burning gas.
Such the cylinder direct injection fuel valve has a general structure in which a hollow injection valve main body containing a needle valve therein is connected by pressure-fit or the like to a housing, within which a solenoid for actuating the needle valve is disposed. The mounting of the injection valve to the cylinder is usually achieved by inserting an injection valve main body into an opening in the cylinder head and the housing of the injection valve is urged under pressure against the cylinder head by a fuel supply pipe.
One example of such cylinder direct injection fuel valve is disclosed in Japanese U.M. Laid-Open No. 7-30368, which employs a complex structure of a specially shaped gasket as well as an O-ring together in order to ensure the seal between the cylinder head and the cylinder direct injecting fuel injection valve urged against it.
However, even with such the complex sealing structure, it was difficult to maintain the seal between the cylinder direct injecting fuel injection valve and the cylinder head with a high reliability for an extended period of time because of high temperature of the cylinder head and high pressure within the combustion chamber. Under these circumstances, it is desirable to develop a highly reliable new seal ring even under high-temperature and high-pressure conditions and yet simple in structure and inexpensive.